Facile Preparation of Layered Ni(OH)2/Graphene Composite from Expanded Graphite

Abstract

A layered Ni(OH)2/graphene composite was firstly prepared by electrochemical deposition of nickel nanoparticles between layers of expanded graphite in Ni2+ containing solution, and then the deposited nickel nanoparticles were converted into Ni(OH)2 via cyclic voltammetry in 6 M KOH electrolyte. Images of transmission electron microscopy show that Ni(OH)2 particles are uniformly distributed on graphene sheets with an average diameter of 6 nm. The Ni(OH)2/graphene composite with an areal loading of 5 mg cm -2 demonstrates a maximum specific capacitance of 856 F g -1 at 1 A g -1 , and 79 % of the specific capacitance can be retained after 2000 cycles at a current density of 10 A g -1 . Commercial expanded graphite is much cheaper than activated carbon and considerably much cheaper than graphene, therefore this technique is very promising for mass production of supercapacitor electrodes.